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regex: Plug a regex literal crash #11938

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Merged
edsiper merged 2 commits into from
Jun 12, 2026
Merged

regex: Plug a regex literal crash #11938

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94716e0
regex: Fix regex literal crash
cosmo0920 Jun 11, 2026
ae73a25
tests: internal: Add test cases for a slash literal
cosmo0920 Jun 11, 2026
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2 changes: 1 addition & 1 deletion src/flb_regex.c
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Original file line number Diff line number Diff line change
Expand Up @@ -129,7 +129,7 @@ static int str_to_regex(const char *pattern, OnigRegex *reg)

option = check_option(start, end, &new_end);

if (pattern[0] == '/' && pattern[len - 1] == '/') {
if (len > 1 && pattern[0] == '/' && pattern[len - 1] == '/') {
start++;
end--;
}
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92 changes: 92 additions & 0 deletions tests/internal/regex.c
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Original file line number Diff line number Diff line change
Expand Up @@ -319,12 +319,104 @@ static void test_option_i_x()
}
}

static void test_literal_slash()
{
struct flb_regex *regex = NULL;
int ret;

regex = flb_regex_create("/");
if (!TEST_CHECK(regex != NULL)) {
TEST_MSG("flb_regex_create failed");
exit(1);
}

ret = flb_regex_match(regex, (unsigned char *) "/tmp", 4);
if (!TEST_CHECK(ret == 1)) {
TEST_MSG("literal slash did not match");
flb_regex_destroy(regex);
exit(1);
}

ret = flb_regex_match(regex, (unsigned char *) "tmp", 3);
if (!TEST_CHECK(ret == 0)) {
TEST_MSG("literal slash matched string without slash");
flb_regex_destroy(regex);
exit(1);
}

ret = flb_regex_destroy(regex);
if (!TEST_CHECK(ret == 0)) {
TEST_MSG("flb_regex_destroy failed");
exit(1);
}
}

static void test_slash_delimited_pattern()
{
struct flb_regex *regex = NULL;
int ret;

regex = flb_regex_create("/tmp/");
if (!TEST_CHECK(regex != NULL)) {
TEST_MSG("flb_regex_create failed");
exit(1);
}

ret = flb_regex_match(regex, (unsigned char *) "tmp", 3);
if (!TEST_CHECK(ret == 1)) {
TEST_MSG("slash-delimited pattern did not match");
flb_regex_destroy(regex);
exit(1);
}

ret = flb_regex_destroy(regex);
if (!TEST_CHECK(ret == 0)) {
TEST_MSG("flb_regex_destroy failed");
exit(1);
}
}

static void test_slash_delimited_literal_slashes()
{
struct flb_regex *regex = NULL;
int ret;

regex = flb_regex_create("//tmp//");

@patrick-stephens patrick-stephens Jun 11, 2026

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Hmm, so we have to use // to get one slash - should we have a different delimiter, e.g. \/?

Just worried we will end up with the nightmare of Java regexes and string escaping otherwise, e.g. if we want two slashes you have to have four, not three, etc.

@cosmo0920 cosmo0920 Jun 12, 2026 •
edited
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No, we have to use double slash in the beginning and the end of regex literals. Not intending on double slash anywhere on the regex literals for our regex engine.

@patrick-stephens patrick-stephens Jun 16, 2026

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Did we do a docs PR btw @cosmo0920 ?

if (!TEST_CHECK(regex != NULL)) {
TEST_MSG("flb_regex_create failed");
exit(1);
}

ret = flb_regex_match(regex, (unsigned char *) "/tmp/", 5);
if (!TEST_CHECK(ret == 1)) {
TEST_MSG("slash-delimited literal slash pattern did not match");
flb_regex_destroy(regex);
exit(1);
}

ret = flb_regex_match(regex, (unsigned char *) "tmp", 3);
if (!TEST_CHECK(ret == 0)) {
TEST_MSG("slash-delimited literal slash pattern matched string without slashes");
flb_regex_destroy(regex);
exit(1);
}

ret = flb_regex_destroy(regex);
if (!TEST_CHECK(ret == 0)) {
TEST_MSG("flb_regex_destroy failed");
exit(1);
}
}

TEST_LIST = {
{ "basic" , test_basic},
{ "uri" , test_uri},
{ "option_ignore_case", test_option_ignore_case},
{ "option_multiline" , test_option_multiline},
{ "option_extend" , test_option_extend},
{ "option_i_x" , test_option_i_x},
{ "literal_slash" , test_literal_slash},
{ "slash_delimited_pattern" , test_slash_delimited_pattern},
{ "slash_delimited_literal_slashes" , test_slash_delimited_literal_slashes},
{ 0 }
};
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